Reputed to be the world’s first structure that implemented the innovative idea of capsule architecture, Kisho Kurokawa designed the Nakagin Capsule Tower based off of his sustainability concept called “Metabolism”, encasing his vision of an architectural movement representative of organic growth and restructuring within buildings.
(photo from Kisho Kurokawa: Metabolism and Symbiosis)

The Nakagin Capsule Tower is a “mixed-system” structure, utilizing both traditional architecture with modern technology within one entity. It is made of two reinforced concrete and steel frame pillars of asymmetric heights, both housing public utilities such as stairs, elevators, plumbing, and electrical systems (Kurokawa 105).
(photos from Beyond Metabolism: The New Japanese Architecture)

The steel frame capsules (which have been designed to be replaceable, removable, and transportable) are prefabricated in specialist factories and assembled at a plant before being delivered to the site. Each one is lifted by mechanical cranes and are attached to the tower shafts using 4 high-tension bolts (Kurokawa 106).
(photo from Kisho Kurokawa architecte: Le Metabolisme 1960-1975)
(photo from Kisho Kurokawa: Metabolism and Symbiosis)
(photo from Kisho Kurokawa: Metabolism in Architecture)

Kurokawa’s design concept focuses on how to make the most efficient use of living space to accommodate the everyday essentials of a person. He borrowed the “capsule” terminology from the aerospace industry (already aware that many spaceships have implemented the idea of efficient area-usage) and retrofitted a rectangular cabin of 8 feet by 12 feet floor space with a built-in bathroom, double bed, desk, storage spaces, TV, tapedeck, typewriter, calculator, clock radio, and a 2-burner stove (Ross 71-72).
(photo from Kisho Kurokawa: Metabolism in Architecture)
(photo from Kisho Kurokawa: Metabolism and Symbiosis)

His design was inspired by a traditional Japanese puzzle game that plays off of interwoven blocks of wood.
(photo from Beyond Metabolism: The New Japanese Architecture)

Following are floor plans of the interlocking system between two capsules (which can be used to accommodate a small family), a one capsule unit, and the bathroom.
(photo from Kisho Kurokawa: From Metabolism to Symbiosis)